The main latch "striker" as we call it (the part that accepts and grabs the button component) can be vulnerable to crushing, resulting in the the part breaking. While fairly uncommon (3%) this is a critical design flaw to be solved before our next production run.
We are in the process of retooling the main "bezel" (the part that is the entire perimeter of the main pack) to incorporate a stronger, integrally supported striker. One good option of the table is to make the striker out of anodized aluminium going forward.
It's unclear if this part had a pre-existing crack or if it took place during assembly, but we've had two Packs that cracked at the centre front.
We're currently testing to see what the potential source of this issue is as well as strengthening that part and protecting any vulnerable areas. Our guess is that the centre is particularly vulnerable during compression (when the pack gets squished, you lean against a wall with it on, etc).
Going forward, we'll have a measurable compression force test which the Packs must pass.
UPDATE: We're re-tooling the main latch to be 10x stronger and have added strengthening "ribs" to the center front to prevent crushing. We've also implemented a quantified test to ensure each part passes these higher strength requirements. Woohoo!